cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A135968 Sum of the distinct prime factors of the Fibonacci number A050937(n).

Original entry on oeis.org

0, 150, 2974, 2443, 62158, 55946694, 2710261050, 555008010, 1547031, 46165377746, 95396546, 92180471494910, 1665088321801550, 364125780, 771601497990, 518283023, 8242065051309594, 32530503217194, 272602401466814027806, 5568053048227732238014, 85526725052226871
Offset: 1

Views

Author

Artur Jasinski, Dec 09 2007

Keywords

Examples

			a(2) = 150 = 37+113 because A050937(2) = 4181 = 37*113.
a(3) = 2974 = 557 + 2417 because A050937(3) = 1346269 = 557*2417.
		

Crossrefs

Programs

  • Mathematica
    k = {}; Do[If[ ! PrimeQ[Fibonacci[Prime[n]]], b = FactorInteger[Fibonacci[Prime[n]]]; c =Length[FactorInteger[b]]; d = 0; Do[d = d + b[[r]][[1]], {r, 1, c}]; AppendTo[k, d]], {n, 1, 50}]; k

Formula

a(n) = A008472(A050937(n)). - R. J. Mathar, Dec 12 2007

Extensions

Edited by R. J. Mathar, Dec 12 2007
a(19)-a(21) from Amiram Eldar, Oct 13 2024

A135970 Fibonacci(Mersenne primes): a(n) = Fibonacci(A000668(n)).

Original entry on oeis.org

2, 13, 1346269, 155576970220531065681649693
Offset: 1

Views

Author

Artur Jasinski, Dec 09 2007

Keywords

Comments

This sequence is a subsequence of A101342. The next term, a(5), has 1712 digits.

Crossrefs

Programs

  • Mathematica
    k = {}; Do[If[PrimeQ[2^n - 1], AppendTo[k, Fibonacci[2^n - 1]]], {n, 1, 15}]; k
    Fibonacci/@Select[Table[2^Prime[n]-1,{n,5}],PrimeQ] (* Harvey P. Dale, May 06 2018 *)
Showing 1-2 of 2 results.